How many days off before you lose fitness?

bump

I remember reading that it takes 10-14 days of inactivity before one realizes a material drop in fitness (assuming the person was well trained to begin with). The biggest change in that time frame is a drop in blood plasma volume.

Don't worry about losing fitness right now. If anything, the time off has given you an unintended taper / recovery. When you do get back to training be very cautious and don't go 100% with your running right away, especially with your mileage. As long as you are doing something, like the bike, that will keep your cardiovascular fitness from declining. A few speed sessions like you did will be good to maintain your speed, as long as they don't exacerbate your injury while you recover.

Remember, if you push yourself too hard through this injury now, you may run a 2:24-5 in 10 days, and then be off for a few months with an even worse injury.

yea, I told me coach I thought it would be best to rest now to avoid serious injury.